1913.] 



NATURAL SCIENCES OF PHILADELPHIA. 



13 



a few of the Somerset specimens show the keeled and tuberculated 

 periphery that is characteristic of the Swift Collection specimens, 

 of which a description is given above. These are, however, of normal 

 size for the species, as may be seen from the plate (figs. 4, 5, 7-9). 

 A few individuals from Benmore show this tuberculated periphery 

 also. 



Contrasted with this smooth condition of the last whorls, which 

 may be considered normal for L. granulosa as found near Mandeville, 

 is the much larger proportion of tuberculated-keeled forms found 



Fig. 1. 



-Lucidella granulosa. Comparison of the dimensions of the forms from 

 five different localities. 



among the specimens from the two localities where the forms are 

 dwarfed. At the Sturridge place, about one-half of the specimens 

 show peripheral granules on the last whorl, though these tend to be- 

 come obsolescent as the lip is approached. In the Kendal Road 

 specimens somewhat over two-thirds show this granulation, and in 

 many cases it extends out to the lip, a much smaller proportion 

 showing this granulation of the peripheral lira becoming obsoles- 

 cent and dying away as the lip is approached than in the case of 



